The present invention relates to a cooling structure for integrated circuits to be used in an electronic device such as a data processor and, particularly, to a cooling structure in which liquid coolant is circulated in the vicinity of the integrated circuits to cool them by transmitting heat generated by these integrated circuits to the liquid coolant.
Examples of a conventional cooling structure for integrated circuits of this type are disclosed in "A Conduction-Cooled Module for High-Performance LSI Devices" by S. Oktay and H. C. Kammerer, published in IBM J RES. DEVELOP., Vol. 26, No. 1, Jan. 1982 and in Japanese Patent Application Disclosure No. Sho 60-160150.
The former example shows a first conventional structure in which a spherical contact surface of a piston is pressed to a heat radiating surface of an integrated circuit formed on a wiring substrate by spring force to transmit heat generated in the integrated circuit through the piston, a gap filled with helium gas, a hat and an intermediate layer and, after heat is transmitted from the intermediate layer to a cooling plate, the latter is cooled by a coolant.
The latter example shows a second conventional cooling structure in which a heat conductive substrate, a deformable heat conductive member and a heat conductive plate are provided on a heat radiating surface of a chip on a printed circuit substrate and an elastically deformable bellows having a thin wall is provided on the heat conductive plate. Cooling is performed by jetting liquid coolant from a nozzle to the heat conductive plate within the bellows.
The cooling structures of the conventional integrated circuit which are disclosed in the above-mentioned articles have defects which will be described below.
First, the heat conduction coefficient obtainable in the first conventional structure is on the order of 0.1 to 0.5 [W/cm.sup.2 .degree.C.] since heat conduction is performed by forced convection of coolant in the coolant passage within the cooling plate. Therefore, the cooling capacity thereof may be lowered when power consumption is increased with increase of integration density of the integrated circuit
Secondly, in the second conventional structure which uses the thin-walled bellows, corrosion of the bellows may occur due to liquid coolant, in which case the coolant may leak, affecting the integrated circuit adversely.